On reaction in the solid state

Using the concept of phonon-lattice interaction, an expression is derived for the minimum temperature, T R , of a solid at which it may enter into solid-state reaction. This expression leads to a more precise idea of single-component reaction (sintering) temperatures than those given by Hüttig. Reaction between two different solids has been re-examined in the light of their physical and crystallographic properties. The rate law for such an additive reaction has been deduced from the quantum rate theory. It is concluded that crystallographic phase transformations and the formation of transitional superstructures constitute the phase-boundary processes and that the kinetics are governed by the dynamics of the diffusion process.